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futurity_sci_tech 00222.txt

#Wi-fi backscatter could make Internet of things real A new method uses radio frequency signals as a power source and reuses existing Wi-fi infrastructure to provide internet connectivity to battery-free devices. Called Wi-fi backscatter this technology is the first that can connect battery-free devices to Wi-fi infrastructure. Imagine a world in which your wristwatch or other wearable device communicates directly with your online profiles storing information about your daily activities where you can best access it all without requiring batteries. Or battery-free sensors embedded around your home could track minute-by-minute temperature changes and send that information to your thermostat to help conserve energy. This not-so-distant nternet of Thingsreality would extend connectivity to perhaps billions of devices. Sensors could be embedded in everyday objects to help monitor and track everything from the structural safety of bridges to the health of your heart. But needing a way to cheaply power and connect these devices to the internet has kept this from taking off. f Internet of things devices are going to take off we must provide connectivity to the potentially billions of battery-free devices that will be embedded in everyday objectssays Shyam Gollakota an assistant professor of computer science and engineering at the University of Washington. e now have the ability to enable Wi-fi connectivity for devices while consuming orders of magnitude less power than what Wi-fi typically requires. he researchers will publish their results at the Association for Computing Machinery s Special interest Group on Data communication s annual conference this month in Chicago. The team also plans to start a company based on the technology. This work builds upon previous research that showed how low-powered devices such as temperature sensors or wearable technology could run without batteries or cords by harnessing energy from existing radio TV and wireless signals in the air. This work takes that a step further by connecting each individual device to the internet which previously wasn t possible. The challenge in providing Wi-fi connectivity to these devices is that conventional low-power Wi-fi consumes three to four orders of magnitude more power than can be harvested in these wireless signals. The researchers instead developed an ultra-low power tag prototype with an antenna and circuitry that can talk to Wi-fi-enabled laptops or smartphones while consuming negligible power. These tags work by essentially ookingfor Wi-fi signals moving between the router and a laptop or smartphone. They encode data by either reflecting or not reflecting the Wi-fi router s signals slightly changing the wireless signal. Wi-fi-enabled devices like laptops and smartphones would detect these minute changes and receive data from the tag. In this way your smart watch could download emails or offload your workout data onto a Google spreadsheet. ou might think how could this possibly work when you have a low-power device making such a tiny change in the wireless signal? But the point is if you re looking for specific patterns you can find it among all the other Wi-fi reflections in an environmentsays coauthor Joshua Smith an associate professor of computer science and engineering and of electrical engineering. The Wi-fi backscatter tag has communicated with a Wi-fi device at rates of 1 kilobit per second with about 2 meters between the devices. They plan to extend the range to about 20 meters and have filed patents on the technology. The University of Washington Commercialization Gap Fund the Qualcomm Innovation Fellowship Washington Research Foundation the National Science Foundation and the University of Washington supported the work. Source: University of Washington You are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license

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